1. Technical Field
The present invention embodiments pertain to geolocating signal sources. In particular, the present invention embodiments pertain to geolocation of multiple unknown signals from radio frequency emitters.
2. Discussion of Related Art
Conventional techniques for geolocation of radio frequency (RF) emitters are commonly based on measurements of received signal strength (RSS) of signals transmitted from the emitter. These conventional geolocation systems usually require a filtering or a transform mechanism to maximize the signal to noise ratio of the target signal based on the known signal characteristics.
However, when a number of signals are coming from different emitter sources, and a number of sensors are used to collect the measured data, each sensor receives a linear combination of the source signals. Neither the structure of the linear combinations nor the waveforms of the source signals are known to the sensors. The signals could be continuous wave, pulsed, swept, narrowband, broadband, etc. In addition, these source signals may overlap in both time and/or in frequency spectrum. The unknown signal characteristics and overlapping source signals present challenges to the conventional geolocation system.